Sea levels will rise higher and faster than previously predicted under drastically revised projections released on Wednesday night by the United Nations’ Intergovernmental Panel on Climate Change.

A new IPCC report says inaction on climate change will likely result in sea level rise of 1.1 metres by 2100 - up from the 2013 projection of more than 90cm. Without action, the seas will be five metres higher by 2300.

Gentoo penguins stand on rocks in Antarctica.Credit:AP

The IPCC report, an update of the IPCC’s 2013 oceans report, warns that already stressed coastlines face bigger waves and storm surges as oceans warm and ice melts. In particular it highlights that ice loss from Greenland and Antarctic glaciers and ice sheets is contributing to accelerating sea level rises.

Low-lying coastal communities face regular extreme flooding by mid-century with some islands and coastal settlements to be made uninhabitable. Even if political action can cap global warming to two degrees Celsius, the report warns that warming oceans and melting sea ice glaciers will raise sea levels by 30 to 60cm by 2100.

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The authors of the IPCC Special Report on the Ocean and Cryosphere in a Changing Climate, released in Monaco on Wednesday night Australian time, say their findings are a stark reminder for governments of the need to slash emissions.

The report comes the same week Prime Minister Scott Morrison was under the global spotlight over his failure to attend the United Nations climate summit in New York, even though he was in the US at the time. Federal Environment Minister Sussan Ley said the report highlighted the importance of addressing emissions and Australia was committed to meeting its international targets.

"Australia is a world leader in the protection and sustainable use of the ocean and we are investing in world leading marine science."

'Faster than expected'

The report highlights how the ocean and the cryosphere – the frozen parts of the planet – play a critical role for life on Earth. About 670 million people live in high mountain regions and 680 million people in low-lying coastal zones and depend directly on these systems. Scientists expect more than one billion people to live by the coast globally by 2050.

“The open sea, the Arctic, the Antarctic and the high mountains may seem far away to many people,” said Hoesung Lee, Chair of the IPCC, “but we depend on them and are influenced by them directly and indirectly in many ways – for weather and climate, for food and water, for energy, trade, transport, recreation and tourism, for health and wellbeing, for culture and identity.

“If we reduce emissions sharply, consequences for people and their livelihoods will still be challenging , but potentially more manageable for those who are most vulnerable,” Lee said.

The report notes changes are occurring faster than expected, and losses from Greenland and Antarctic glaciers and ice sheets in particular are contributing to sea level rise. It also predicts that glaciers in Europe, eastern Africa, the tropical Andes and Indonesia will lose more than 80 per cent of their current ice mass by 2100 under high emission scenarios.

With further warming, flooding events that occurred once per century in the past will occur every year by mid-century in many places.

In Australia 80 per cent of the population live within 50 kilometres of the coast. Government reports have already warned of inundation in bayside suburbs such as Elwood and Altona in Melbourne and Collaroy-Narrabeen in Sydney.

Icebergs float away as the sun rises near Kulusuk, Greenland. Scientists are trying to understand the alarmingly rapid melting of the ice. Credit:AP

The IPCC also warns of increased coral bleaching, more storms triggering coastal flooding, declining fish stocks and threats to food security. Even if emissions are cut the Great Barrier Reef is changing.

But it also highlights the extreme conditions experienced in Tasmania in the summer of 2015-2016 as an example of the risks of marine heatwave and the impact of multiple events, including bushfire, coinciding.

That summer Tasmania’s shellfish and fisheries suffered widespread disease with economic losses to Tasmania estimated to have been about $442 million.

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Days on the beach

“Rising sea levels would impact on our coastlines and projected increasing warming and wave heights in the Southern ocean are likely to exacerbate problems such as coastal erosion that are already being felt in many coastal communities along our southern coastlines.”

Dr McInnes said the special report reinforced the need to to keep global warming to well below 2 degrees above pre-industrial levels while trying to limit warming to 1.5 degrees – the Paris Agreement target. She said it was now urgent that the world move to low emissions technology in energy, land and ecosystems, urban and infrastructure and industry.

The Australian Conservation Foundation said the IPCC report was a timely reminder of Australia’s obligation to step up action on cutting emissions to help protect its coast.

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“Australians love days on the beach and getting out on the water – 21 million of us live within 50 kilometres of the coast – runaway climate change challenges all this and more,” said Australian Conservation Foundation Chief Executive Officer, Kelly O’Shanassy. “If we continue polluting our atmosphere, the oceans will continue to cop it – and humans will bear the costs."

Australian Coastal Councils Association chair Barry Sammels said houses would “absolutely” be lost if sea levels rose by 1.1 metres. He called for urgent action from all three levels of government to tackle the impact of rising seas.

Australian National University climate experts say the new IPCC report is a “wake-up call to the world about the devastating consequences of failing to act to address climate change". Associate Professor Nerilie Abram is a lead author of the IPCC report and said that despite the grim picture the report paints for Australia’s coast, there was still time to avoid the worst scenario.

The IPCC is made up of 195 IPCC member governments. More than 100 authors from 36 countries assessed the latest scientific literature related to the ocean and cryosphere, referencing about 7000 scientific publications.

A Victorian government spokeswoman said the government would consider the IPCC report as it finalised its marine and coastal policy.

NSW Environment Minister Matthew Kean said his government was taking "decisive" action on climate change. "Our government was elected on a policy of net zero emissions by 2050 and we are working towards delivering that," he said.

"The NSW Government monitors sea levels and is providing $83.6 million to help coastal communities respond to coastal management challenges.”